Audio Merchant <= 5.0.4 - Cross-Site Request Forgery to Arbitrary File Upload

Description

The Audio Merchant plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 5.0.4. This is due to missing or incorrect nonce validation on the function audio_merchant_add_audio_file function. This makes it possible for unauthenticated attackers to upload arbitrary files via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.